The Case IH STX450QT tractor cooling system capacity is 20 gal | 75.7 L, coolant type is extended-life OAT coolant, and coolant change interval is every 1,000 hours.
Case IH STX450QT Coolant Capacity Details
Cooling system capacity
20 gal | 75.7 L
Coolant type
Extended-life OAT coolant
Coolant change interval
Every 1,000 hours
Coolant mixture ratio
50/50 antifreeze and water
Radiator cap pressure
7 psi | 48 kPa
Coolant Capacity Comparison Chart
Coolant Capacity Comparison
This model
20 gal
Average
16 gal
Low
10 gal
High
28 gal
Benchmarks use practical low, average and high coolant-capacity ranges for the large ag tractor category. Use the exact tractor manual before buying coolant.
Case IH STX450QT Extra Coolant Notes
Engine horsepower
450 hp | 335.6 kW
Engine displacement
14.9 L | 912 cu in
Capacity note
For the Case IH STX450QT, the listed cooling system capacity is 20 gal | 75.7 L. Buy slightly more coolant than the exact capacity so you have enough for topping off after air burps out.
Mixture note
50/50 antifreeze and water.
Radiator cap note
The radiator cap pressure listed for the Case IH STX450QT is 7 psi | 48 kPa. Do not replace it with a random cap unless the pressure rating matches.
Refill note
Refill slowly, run the tractor until warm with the heater circuit open if fitted, let it cool, then recheck the coolant level. Never remove a hot radiator cap under pressure.
Case IH STX450QT Coolant FAQs
How much coolant does a Case IH STX450QT take?
The Case IH STX450QT takes 20 gal | 75.7 L of coolant. That is about normal for the large ag tractor benchmark shown here, so plan it like a standard drain-and-refill rather than a tiny top-up.
Is the Case IH STX450QT coolant capacity normal?
Yes, 20 gal | 75.7 L lands about where you would expect for this tractor category. The main thing is buying enough for a complete refill plus a small top-off amount.
How many coolant jugs do I need for a Case IH STX450QT?
Do not underestimate this refill. A 20 gal | 75.7 L system needs about 20 one-gallon containers if you are using premixed coolant. If using concentrate at a 50/50 mix, plan on about 10 gal of concentrate and 10 gal of distilled water. In metric terms, that is roughly 16 x 5 L containers for a full premix refill.
Can I mix coolant types in a Case IH STX450QT?
Because the listed coolant is extended-life OAT coolant, the clean move is to stay with the same approved chemistry. Do not casually mix it with old green conventional coolant; if the old coolant type is unknown, flush first or confirm what is already in the system. The listed mix is 50/50 antifreeze and water, so do not run straight water except as a short emergency move.
How much concentrate and water does a Case IH STX450QT need?
With the listed 50/50 antifreeze and water mix, a full 20 gal | 75.7 L refill works out to about 10 gal of antifreeze concentrate and 10 gal of distilled water. If using premix, do not add extra water unless the product label says to.
Can I use a different radiator cap on a Case IH STX450QT?
The listed cap pressure is 7 psi | 48 kPa. That is a lower-pressure cap, so do not upgrade it to a higher-pressure cap just because it sounds stronger. Too much cap pressure can stress hoses, radiator seams and older seals.
Official information note
Mistakes do happen. Coolant specs can change by year, engine, market, radiator option and coolant chemistry. Check the operator manual, parts book and official caseih.com website before draining, flushing or refilling the cooling system.
